Previously, Patent Document 1, Patent Document 2, and Patent Document 3 disclose a technique of generating and displaying images in which luminance components corresponding to left and right eyes are differ from each other. In Patent Document 1, by setting the luminance of one of left and right images to be relatively higher, and in Patent Documents 2 and 3, by enhancing a contrast of one of the images, a three-dimensional appearance and luster are achieved.
FIG. 11 is a view showing an example of an image processing device of a related art. An image processing device 300 of the related art is composed of a both eye images display unit 301, a right image luminance correcting unit 302, and a left image luminance correcting unit 303. The both eye images display unit 301 includes a right image display unit 304 and a left image display unit 305. An input image signal is input to each of the right image luminance correcting unit 302 and the left image luminance correcting unit 303. The right image luminance correcting unit 302 enhances a light-dark contrast after extracting a luminance Y from the image signal.
As an example of a contrast enhancement method, there is a method that applies a first tone curve 51 shown in FIG. 12 to the luminance Y. The left image luminance correcting unit 303 corrects the luminance by using a parameter which is different from that of the right image. As an example of the left image luminance correcting unit 303, there is a method that apples a second tone curve 52 to the luminance Y. The second tone curve 52 has a slope less than that of the first tone curve 51, and has a characteristic that a contrast enhancement effect is low.
The both eye images display unit 301 is a display device which is capable of presenting different images to right and left eyes of a human, and is utilized as a three-dimension display. As an example of the both eye images display unit 301, there is one in which a left and right image projection units are mounted with different polarization filters and an observer observes with both eyes through polarization glasses.    [Patent Document 1]    Japanese Unexamined Patent Application Publication No. 10-224822    [Patent Document 2]    Japanese Unexamined Patent Application Publication No. 2004-229881    [Patent Document 3]    Japanese Unexamined Patent Application Publication No. 11-511316